1. Field of the Invention
The present invention relates to an image forming apparatus.
2. Description of Related Art
Regarding a conventional image forming apparatus such as a printer, a copying machine, a facsimile machine and a multifunctional machine, in a printer as an example, an exposure unit exposes light on a photosensitive drum on which a charging unit uniformly charges electricity to form an electrostatic latent image, a developing unit develops the electrostatic latent image to form a toner image on the photosensitive drum, and then the toner image is transferred onto a paper sheet and fixed thereon.
The developing unit has a developing roller configured to adhere toner on an electrostatic latent image on the photosensitive drum, a toner supply roller configured to supply toner to the developing roller and a development blade configured to form a thin toner layer on the developing roller. The toner supplied from the toner cartridge to the developing unit is charged by development voltage applied to the developing roller and supply voltage applied to the toner supply roller and charged by a triboelectrification between the developing roller and toner supply roller and between the developing roller and development blade. This technology is disclosed, for example, in Japanese Patent Application Laid-Open No. 2002-169343.
However, in such a conventional printer, as an unoperated period which is the time period from an end of a print job to a beginning of a subsequent print job, become longer the image quality may deteriorate due to fogging, which is a phenomenon in which toner adheres in non-image areas on a paper sheet.